U.S. patent application number 17/390431 was filed with the patent office on 2022-03-24 for gasless, mechanized, field-welding of tubular structure.
The applicant listed for this patent is Pipeline Supply and Service LLC. Invention is credited to Marcus Cook, Peter Nicholson.
Application Number | 20220088697 17/390431 |
Document ID | / |
Family ID | 1000005813637 |
Filed Date | 2022-03-24 |
United States Patent
Application |
20220088697 |
Kind Code |
A1 |
Cook; Marcus ; et
al. |
March 24, 2022 |
Gasless, Mechanized, Field-Welding Of Tubular Structure
Abstract
A system and method provide gasless, mechanized, field welding
of an exterior of a tubular structure such as a pipeline, without
the need for an enclosure. An embodiment consolidates some of the
welding equipment on a skid for ease of transport to and from a
remote worksite. The gasless weld may be achieved despite the
presence of wind, by precisely controlling an arc voltage as
disclosed. The footprint and weight of the system may be minimized,
along with the associated labor, expense, and environmental impact
otherwise incurred by conventional welding techniques using
enclosures.
Inventors: |
Cook; Marcus; (Houston,
TX) ; Nicholson; Peter; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pipeline Supply and Service LLC |
Houston |
TX |
US |
|
|
Family ID: |
1000005813637 |
Appl. No.: |
17/390431 |
Filed: |
July 30, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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63080413 |
Sep 18, 2020 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23K 9/0282 20130101;
B23K 9/1087 20130101; B23K 9/0953 20130101; B23K 9/0052 20130101;
B23K 9/327 20130101 |
International
Class: |
B23K 9/32 20060101
B23K009/32; B23K 9/095 20060101 B23K009/095; B23K 9/10 20060101
B23K009/10; B23K 9/00 20060101 B23K009/00 |
Claims
1. A system for welding a tubular workpiece, the system comprising:
a plurality of welding equipment for transportation to a work site,
the welding equipment including a welding machine for generating a
controlled voltage, a power supply for powering the welding
machine, and a boom including a lifting arm; a helper station
secured to the lifting arm, positionable to orient the helper
station with respect to the tubular workpiece to be welded; a wire
feeder carried on the helper station, the wire feeder configured
for feeding a consumable welding wire; a gasless torch in
electrical communication with the welding machine and configured
for receiving the consumable welding wire from the wire feeder and
generating an electrical arc between the consumable welding wire
and the tubular workpiece; a guide track positionable about the
tubular workpiece; and a mechanized carrier moveably secured to the
guide track and moveable along the guide track while holding the
gasless torch adjacent to the tubular workpiece.
2. The system of claim 1, further comprising: a coaxial voltage
cable comprising an inner wire disposed within an outer wire
separated by an insulating layer, the coaxial cable supplying the
controlled voltage from the welding machine to the gasless
torch.
3. The system of claim 1, further comprising: a voltage sensor
included on the gasless torch for sensing an arc voltage at the
tubular workpiece; wherein the welding machine is configured for
adjusting the controlled voltage supplied by the welding machine to
the torch in response to the arc voltage sensed by the voltage
sensor.
4. The system of claim 3, wherein a magnitude of a difference
between the controlled voltage supplied by the welding machine and
the arc voltage sensed by the voltage sensor is less than 1 volt
(V).
5. The system of claim 1, further comprising: a user interface in
electrical communication with the mechanized carrier, for
controlling one or both of motion of the mechanized carrier along
the guide track and lateral position of the gasless torch relative
to the weld path in response to real-time user input during welding
of the tubular workpiece.
6. The system of claim 1, further comprising: an automatic
controller in electrical communication with the mechanized carrier,
the automatic controller comprising an optical sensor for sensing a
position of the mechanized carrier and for controlling motion of
the mechanized carrier along the guide track in response to the
sensed position.
7. The system of claim 1, wherein an enclosure is not provided
about the tubular workpiece when welding the tubular workpiece.
8. The system of claim 1, further comprising: a skid supporting at
least the welding machine and the boom, the skid being transported
to a work site on a transport vehicle.
9. The system of claim 8, wherein the transport vehicle comprises:
a band of non-metal treads driven by two or more wheels.
10. The system of claim 9, wherein the lifting arm is moveably
supported on the skid to adjust the position of the helper station
with respect to the tubular workpiece at least by moving the
lifting arm.
11. The system of claim 8 whereas the skid is transportable on a
transport vehicle without disassembly.
12. The system of claim 1, further comprising one or more user
controls for a user to operate one or more of the welding machine,
the wire feeder, and the boom.
13. The system of claim 1, wherein the tubular workpiece comprises
one or more pipeline segments to be welded end-to-end.
14. The system of claim 13, wherein the weld path is along an
interface between two adjacent pipeline segments end-to-end.
15. The system of claim 1, wherein the weld path is along a portion
of a pipeline to be repaired.
16. The system of claim 1, further comprising: a collapsible cover
coupled to the boom, the collapsible cover moveable between an
expanded position that covers an area overhead of one or more of
the helper station, the mechanized carrier, and a portion of the
tubular workpiece including the weld path, and a collapsed
position.
17. The system of claim 1, further comprising: an attachment
mechanism for interchangeably supporting the gas shielded/gasless
torch or one or more other tools, the one or more other tools
selected from the group consisting of a paint sprayer and a sand
blaster.
18. The system of claim 1, wherein the power supply comprises a
chassis having a maintenance panel and an electrical outlet panel
on a same side of the chassis.
19. The system of claim 1, further comprising: a wireless
connection configured for data gathering and/or transmission from
the skid and/or helper station to a remote location.
20. A portable helper station for welding a workpiece, the helper
station comprising: a frame positionable to orient the helper
station with respect to the workpiece, the frame transportable to a
welding site and removably securable to a lifting arm; a wire
feeder carried on the frame, the wire feeder configured for feeding
a consumable welding wire to a gas shielded or gasless torch in
electrical communication with a welding machine to generate an
electrical arc between the consumable welding wire and the
workpiece; and a user interface electrically connected and
physically mountable on the frame, including at least a first
controller configured to operate the wire feeder.
21. The portable helper station of claim 20, further comprising: a
guide track removably positionable about the workpiece; and a
mechanized carrier moveably secured to the guide track and moveable
along the guide track while holding the gas shielded or gasless
torch adjacent to the workpiece, the mechanized carrier in
electrical communication with the user interface; and wherein the
guide track and mechanized carrier are transportable to the welding
site.
22. The portable helper station of claim 21, wherein the workpiece
is a tubular workpiece and the guide track is oriented along a
circumference of the tubular workpiece to guide the mechanized
carrier along the circumference of the tubular workpiece.
23. The portable helper station of claim 21, wherein the user
interface is further for remote control of a welding process
including one or both of motion of the mechanized carrier along the
guide track and lateral position of the gas shielded or gasless
torch relative to the weld path in response to real-time user input
during welding of the workpiece.
24. The portable helper station of claim 20, wherein the lifting
arm is controllable by the user interface to raise, lower, and/or
rotate the lifting arm.
25. The portable helper station of claim 20, further comprising: a
coaxial voltage cable comprising an inner wire disposed within an
outer wire separated by an insulating layer, the coaxial cable
supplying the controlled voltage from the welding machine to the
gas shielded or gasless torch.
26. The portable helper station of claim 20, further comprising: a
voltage sensor included on the gas shielded or gasless torch for
sensing an arc voltage at the workpiece; and wherein the welding
machine is configured for adjusting the controlled voltage supplied
by the welding machine to the torch in response to the arc voltage
sensed by the voltage sensor.
27. The portable helper station of claim 20, further comprising: an
attachment mechanism for interchangeably supporting the gas
shielded or gasless torch or one or more other tools, the one or
more other tools selected from the group may consist of a paint
sprayer, sand blaster, heating apparatus or any other apparatus
28. The portable helper station of claim 20, further comprising: a
collapsible cover securable to the lifting arm, the collapsible
cover moveable between an expanded position and a collapsed
position, wherein the collapsible cover covers an area overhead of
at least the helper station in the expanded position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a non-provisional of U.S. Patent
Application No. 63/080,413, filed on Sep. 18, 2020, the entire
disclosure of which is incorporated herein by reference.
BACKGROUND
[0002] Welding is a common technique in manufacturing for joining
any number of components of similar composition to form a structure
of virtually any desired size. Welding is commonly used to join
many types of metals, as well as certain plastics. Most types of
welding involve melting a portion of the pieces to be joined near
an interface between those pieces. The melted material runs
together and re-hardens as it cools, so that the two pieces become
an essentially unitary structure. This provides an advantage over
other joining processes like soldering and welding, in which a
filler metal is instead melted at the interface, leaving two
distinct parts joined by the solidified filler material. Other
types of welding known in the art generally as "solid-state"
welding do not melt the parent material. However, these are
generally not suitable for larger structures.
[0003] Pipelines are among the many large structures that can be
formed by welding. Pipelines are long vessels constructed to carry
fluids, such as petroleum, chemicals, water, or sewage over long
distances, from the source to some downstream destination where the
fluids may be processed and/or sold. Multiple pipeline segments may
be consecutively arranged end-to-end and joined to create a
pipeline extending hundreds or thousands of miles or kilometers
long. The enormity of such a structure, however, presents numerous
challenges in its fabrication. The resulting economic and
environmental impact can be significant.
[0004] Currently, many pipelines are constructed using gas-shielded
welding techniques to achieve the desired weld quality needed to
safely convey fluids and minimize the risk of failure or leakage.
Gas-shielded techniques involve supplying an inert gas to the joint
to displace oxygen and other contaminants that would otherwise
degrade the quality of the weld joint. The use of gas-shielded
welding on pipelines, in turn, requires the use of large enclosures
(alternately referred to as shacks, huts, or houses) around every
pipeline joint to be welded, such as shown in FIG. 1. These large
enclosures are necessary, in part, to shield the pipeline joint to
be welded from wind common to large, open spaces. Such wind and
other external factors would otherwise blow away the inert gas
supplied to the joint. Various welding equipment is also mounted to
these large enclosures, adding to their size, weight, and cost. The
shacks, in turn, require significant expenditures of human
resources, equipment and capital especially if their location need
to be in tight environmental terrains. One such terrain would be a
trench as shown in FIG. 2. As can be seen, the trench requires an
enormous amount of excavation to accommodate these shacks.
[0005] Transportation and implementation of these large enclosures
introduces its own set of costs and challenges. For example,
special vehicles having metal, tank-like treads or tracks are
needed to transport them. The metal tracks can damage road
surfaces, and the regulatory requirements in place to mitigate this
damage adds to the cost and complexity. On-site, the use of these
large enclosures also requires excavation of large portions of
earth, with resulting environmental and economic impact.
[0006] The industry is always looking for new and better ways to
reduce costs and minimize environmental impact. The present
disclosure, having identified the foregoing needs, will now address
these risks with various systems, devices, and methods that may
represent a step-change improvement in how pipelines and other
large, tubular structures may be constructed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an elevation view of a pipeline under construction
requiring the use of large enclosures known as shacks.
[0008] FIG. 2 is an elevation view of the pipeline as lowered into
a trench as it is being built, as an example of the very large size
of trench required for receiving such a shack.
[0009] FIG. 3 is a schematic, plan view of a welding system for
welding a tubular workpiece according to an embodiment of this
disclosure.
[0010] FIG. 4 is a side view of an example implementation of the
welding system of FIG. 3.
[0011] FIG. 5 is a perspective view of the tubular workpiece on
which the guide track and mechanized carrier are installed
[0012] FIG. 6 is a side view of an example implementation of the
helper station with various equipment installed on or connected
thereto.
[0013] FIG. 7 is a side view of the wire feeder carried on the
helper station.
[0014] FIG. 8 is a perspective view of the gasless torch connection
at which voltage is locally measured.
[0015] FIG. 9 is a cutaway view of an example coaxial cable for
facilitating low-impedance, high-accuracy control of the voltage at
the gasless torch connection.
DETAILED DESCRIPTION
[0016] A system and method are disclosed for gasless, mechanized,
field welding of an exterior of workpiece. In some examples, the
workpiece may be a tubular structure such as a pipeline. Gasless
welding may be performed in the field without an enclosure, even in
the presence of wind. The footprint and weight of the system may be
minimized, along with the associated labor, expense, and
environmental impact otherwise incurred by conventional welding
techniques using enclosures.
[0017] In an example embodiment, the enclosure is eliminated via
the use of gasless welding techniques, which do not require an
auxiliary inert gas supply during welding. The gasless welding may
be achieved in the field with a system configuration that combines,
for example, precise local voltage measurement of the arc at a
workpiece to be welded, low-inductance power and signal
transmission using a coaxial cable coupling the gasless torch to a
welding machine, and precisely controlled height of the torch from
the workpiece using a mechanized carrier that travels along the
workpiece on a guide track. In some examples, the guide track is
generally circular to conform with a tubular workpiece, although
other guide tracks may be configured to move along straight
sections or non-circular sections. By eliminating the need for an
enclosure, particularly when welding a pipeline in the field, and
by optionally consolidating various welding equipment on a skid
that can be relocated on a transport vehicle without disassembly,
the size, weight, and footprint occupied by the welding equipment
may be greatly reduced as compared with conventional pipeline
welding.
[0018] This disclosure is also directed, in part, to a portable
helper station for welding a workpiece in the field. The portable
helper station may be a subset of a larger system disclosed herein,
which may be field assembled with any of a variety of other
equipment. The helper station may be used in conjunction with a
gasless welding system and method such as described herein.
Alternatively, the helper station may be configured for use with a
gas shielded system and method.
[0019] In an example embodiment, the helper station comprises a
frame positionable to orient the helper station with respect to the
workpiece to be welded. The frame is transportable to a welding
site and removably securable to a lifting arm, which may be a
mechanized lifting arm (e.g. electrically and/or hydraulically
raised, lowered, and/or rotated). A wire feeder may be carried on
the frame, for feeding a consumable welding wire to a gasless torch
in electrical communication with a welding machine that is
interconnected with the helper station in the field. The wire
feeder and gasless torch may generate an electrical arc between the
consumable welding wire and the workpiece. A user interface may be
electrically connected and physically mountable on the frame. The
user interface may have at least a first controller configured to
operate the wire feeder, and one or more other controllers such as
to control the motion of the lifting arm, the motion of mechanized
carrier on a track, and/or the position of the gasless torch with
respect to the mechanized carrier.
[0020] For purposes of this disclosure, there are four main
categories of welding identified. These are generally categorized
according to the level of human intervention required. A first
category is manual welding, which involves a hand-held electrode or
"stick" above the workpiece. The stick gets consumed while welding,
and the user may manually adjust a spacing between the stick and
the workpiece. A second category is semi-automated welding using a
hand-held torch. A continuous electrode may be fed to the torch,
and an inert gas may be supplied from the torch to protect the
weld. A third category is mechanized welding, wherein the torch,
itself is guided by a device, and a human provides active,
electronic control input to make minor adjustments to the device
while welding. An inert gas may also be supplied to protect the
weld. An example of a mechanized welding system is the Bug and
Band.TM. family of welding systems provided by Pipeline Supply
& Service, LLC. In a Bug and Band system, a band disposable
about a circular workpiece in the vicinity of a joint to be welded
provides a track to guide a welding device (the "bug") that moves
along the track in response to human input. A fourth category is
automated welding, in which a robot performs the entire weld from
start to finish, generally without active human input during the
welding.
[0021] As used in any of the following embodiments, the "torch" may
refer to a welding gun, that can be alternately referred to as a
torch, gun, or welding torch. The torch may be the mechanism that
is nearest the work piece being welded where the welding wire
exits.
[0022] FIG. 3 is a schematic, plan view of a welding system 10 for
welding a tubular workpiece 20 according to an embodiment of this
disclosure. The tubular workpiece 20 may be at a worksite 5. The
worksite 5 may be exposed to an abundance of wind 15 as would
typically be present in large, open places where pipelines are
constructed. And yet, the system 10, according to the gasless
welding and other various aspects below, may weld without the need
for a weld shack such as in FIG. 1.
[0023] The tubular workpiece 20 may be any generally tubular
structure formed of a base material that can be welded. The tubular
workpiece 20 may be referred to in specific examples as a pipeline
20 or pipeline segment by way of example and not by limitation. The
tubular workpiece 20 may be a ferrous or non-ferrous metal although
aspects of this disclosure may be applied to any tubular structure
of weldable material. The tubular workpiece 20 is also of generally
circular cross-section in this example, although a tubular
workpiece need not have a circular or perfectly-round
cross-section, and so other shapes are also within the scope of
this disclosure in terms of what may be welded. The weld may be
performed, for example, along an interface between two pipeline
segments butted end-to-end. Alternatively, the weld may be
performed along a portion of the tubular workpiece 20 to be
repaired, such as a crack.
[0024] The system 10 in this example includes a plurality of
welding equipment transportable to a work site 5, optionally on a
skid 12 and without disassembly prior to transport. Thus,
substantially all of the equipment mounted on the skid may remain
assembled/secured to the skid during transport if desired. The
welding equipment on the skid 12 in FIG. 3 includes, for example,
at least one welding machine 30 (two redundant units are shown
here) for generating a controlled voltage, a power supply 40 for
powering the welding machine 30, and a boom 50 including a lifting
arm 52. Additional welding equipment may be provided at a helper
station 60. The power supply 40 may generate or otherwise supply
electrical power to be used by the welding machines 30 and other
equipment discussed herein. A main power input schematically shown
at 42 provides the power of whatever kind consumed by the power
supply 40 itself. For instance, the main power input 42 may be a
main electrical power source provided for this skid 12 and for
various other systems on the worksite 5, however that may be
supplied, such as by on-site generators, a connection to local
power grid, and so forth. The power supply 40 may generate a
specific range or set of one or more electrical current parameters
suitable for at least the welding machines 30. Optionally, the
welding machines 30 and/or the power supply 40 could be configured
to also generate a specific range or set of one or more electrical
current parameters suitable for use by the various other equipment
in the system 10, such as specific voltage and current parameters
of direct current (DC) and/or alternating current (AC) used by
different equipment.
[0025] The system 10 may also support wireless data gathering and
transmission from the skid or helper to a remote location (cloud,
onsite data center, customer data center, data center, etc.)
Electrical and data lines may be provided as needed between any of
the various welding equipment, using any of a variety of cables,
connectors, buses, wires, wiring harnesses, wireless connections of
various protocols, and so forth. Some of these connections are
indicated by way of example with dashed lines in FIG. 3. Electrical
power and data or communication cables 54 are also shown routed
along the boom 50 from components of the system 10 on the skid 12
to components of the system 12 at the helper station 60. It should
be understood that physical and/or wireless connections can be made
as needed, directly or indirectly, between different components of
the system 10, and not every possible combination of electrical
power and signal data communication is indicated in the
drawing.
[0026] The welding machines 30, power supply 40, boom 50, and/or
other welding equipment (although not necessarily all the welding
equipment) are optionally mounted in this embodiment on a skid 12,
for transportability of at least a portion of the welding system 10
to and from a work site where the pipeline or other tubular
workpiece 20 is to be welded. The skid 12 may be any portable
structure to which some of the welding equipment may be mounted to
transport that welding equipment on the skid to and from a worksite
5. The skid 12 in this example is an open structure for easy user
access to the welding equipment mounted thereon. It may have a
strong frame for the welding machine(s) 30, power supply 40, boom
50, and other welding equipment to be mounted to. The skid 12 and
various equipment on it may be assembled and/or stored when not at
the work site, such as at a remote storage or service facility (not
shown).
[0027] The skid 12 and welding equipment mounted thereon may then
be readily loaded onto and unloaded from a transport vehicle 14,
depicted as a flatbed truck in this example. Conventional lifting
equipment may be used to load or unload the skid 12 from the
transport vehicle 14, such as using the tines of a forklift 16.
Depending on the particular worksite and the job to be performed
there, the skid 12 may either remain on the transport vehicle 14
while the welding job is completed, or unloaded from the transport
vehicle 14 at the worksite. Because the system 10 is capable of
welding a pipeline or other tubular structure outdoors without an
enclosure to protect from the wind 15, the weight of a conventional
welding shack can be eliminated. The weight of the skid 12 and the
equipment mounted on the skid 12 may be very light weight in
comparison. In at least some embodiments, the weight of the skid 12
and the welding equipment mounted thereon is less than about 7500
pounds (3400 Kg) in some embodiments, or up to 8500 pounds (3900
Kg) when including an expandable cover. As a result, the skid 12
may be easily transported to and from the worksite 5 without the
heavy metal treads and special transportation measures and
precautions normally associated with pipeline construction. Whereas
conventional methods may require the use of metal treads to support
the weight of a shack, the transport vehicle 14 in the present
system may use non-metal (e.g. rubber) treads driven by one or more
wheels, or even conventional tires such as in the example of a
truck. This makes it easy to load the welding equipment onto a wide
variety of transport vehicles with a much lower risk of damage to
the roadways. However, although helpful, the skid and transport
vehicle are not strictly required in every configuration. If
desired, components of the system 10 could be individually
transported and then assembled at the worksite 5.
[0028] Referring still to FIG. 3, the helper station 60 is secured
to and suspended from the lifting arm 52 of the boom 50. The helper
station 60 may comprise a frame 61 for supporting various
equipment. The helper station 60 is configured, in part, for the
convenience of a human user who may monitor and/or participate in
the mechanized welding of the tubular workpiece 20. The helper
station 60 is positionable at the worksite to orient the helper
station 60 with respect to the tubular workpiece 20 to be welded
and the human user who may operate it. For example, the skid 12
itself may be positioned and oriented at the worksite to position
the helper station 60 near the tubular workpiece 20 to be welded.
Further, the boom 50 may be moveable with respect to the skid 12,
such as by raising or lowering the lifting arm 52 about an axis 53,
or azimuthally by rotation of the lifting arm 52 about a pivot as
indicated at 55. Thus, placement of the skid 12 and/or positioning
of the lifting arm 52 may be used to bring the helper station 60
into proximity of the tubular workpiece 20 so that various other
equipment is easily accessible by the user.
[0029] The helper station 60 is physically accessible to a human
user who may perform or help with various aspects of welding the
pipeline 20 using various input devices and with the help of the
mechanized equipment disclosed. For example, the human user may be
a skilled welder, who may be stationed at the helper station 60
within visual distance from the tubular workpiece 20 to visually
monitor and adjust the weld process if needed. The helper station
60 carries one or more automatic wire feeder 70 for feeding a
consumable welding wire 72 to a gasless torch 62 in electrical
communication with the welding machine 30. The gasless torch 62
receives the consumable welding wire 72 as it is fed from the wire
feeder 70. The gasless torch 62 receives a controlled voltage from
the welding machine(s) 30 to generate an electrical arc between the
consumable welding wire 72 and the tubular workpiece 20. Any number
of user interfaces are electrically connected and optionally
physically mountable on the helper station 60, such as a first
controller 76 and a second controller 78 further discussed below.
The first controller 76 may be used to operate the wire feeder 70,
and the second controller 78 may provide for remote control of the
welding process, for example. One of these or another controller
may be used to control the boom.
[0030] The system 10 includes mechanized equipment in this example,
to help control aspects of the welding process that may be harder
for a human user to adjust. In particular, the system 10 includes a
guide track 22 that is positionable about the tubular workpiece 20.
The tubular workpiece 20 in this example has a circular
cross-section and the guide track 22 may be shaped to conform to
the cross-sectional shape. In this case the cross-sectional shape
is circular, but a guide track may alternately be configured for
other cross-sectional shapes (e.g. square or hexagonal tubing). A
mechanized carrier 24 is moveably secured to the guide track 22 and
moveable along the guide track 22, to guide the gasless torch 62 at
a precise, controlled distance from the tubular workpiece 20. Any
of a variety of tracks may be configured according to this
disclosure whereby a mechanized carrier is moveably secured to the
track. Just one example of a suitable track and mechanized carrier
is the Bug and Band.TM. system offered by Pipeline Supply &
Service, LLC, wherein the "band" comprises the track and the "bug"
comprises the mechanized carrier. Instead of the human operator
manually holding the gasless torch 62 by hand, the gasless torch 62
is clamped to the mechanized carrier 24, and the mechanized carrier
24 moves along the guide track 22 while holding the gasless torch
62 adjacent to the tubular workpiece 20 to weld along a weld path
26. This contributes, in part, to performing a quality weld, such
as by holding the gasless torch 62 at a consistent distance from
the tubular workpiece 20 and creating a uniform, quality weld
bead.
[0031] A user interface is provided in electrical communication
with the mechanized carrier 24, for controlling one or both of
motion of the mechanized carrier 24 along the guide track 22 and a
lateral position of the gasless torch 62 relative to the weld path
26, in response to real-time user input during welding of the
tubular workpiece 20. The user interface in this example comprises
a first controller 76 having a graphical user interface (GUI) for
controlling the wire feeder 70 and a second controller 78 for
controlling movement of the mechanized carrier 24 along the guide
track 22. Any of a variety of inputs may be provided on these
handheld controllers 76, 78, such as physical or electronic
buttons, dials, switches, and the like, or an interactive
touchscreen. For example, the second controller 78 may be used to
selectively start and stop the welding process and coordinated
movement of the mechanized carrier 24 along the guide track 22. The
second controller 78 may also be used to control a relative
position of the gasless torch 62, such as the lateral position, for
the human operator to follow the intended well path 26.
[0032] Although the system 10 of FIG. 1 is configured for
assistance by a human operator, alternative embodiments may instead
use an automatic controller in electrical communication with the
mechanized carrier 24. For example, the automatic controller may
comprise an optical sensor for sensing a position of the mechanized
carrier 24 relative to the tubular workpiece 20 and the weld path
26. The optical controller may control motion of the mechanized
carrier 24 along the guide track 22 in response to the sensed
position, such as to start/stop and steer left/right to closely
track the desired weld path 26. Then, instead of hand-held
controllers 76, 78, the automatic controller may be wired into or
otherwise included with control logic, which may be provided on or
in connection to the helper station 60.
[0033] In addition to eliminating the need for a bulky, heavy shack
or other weld enclosure, the arrangement and configuration of the
welding equipment on the skid 12 results in a desirably very
compact system with a relatively small footprint. In a further
aspect, the power supply 40 has a cabinet with one-sided access.
Everything the human user may need to access is available on the
same side 44 of its chassis. For instance, the electrical outlets
and maintenance panel may be both accessible from the same side 44.
This may avoid the need for standing room on the opposite side 46
of the chassis 44 indicated with an "X."
[0034] Additional figures are provided to show particular example
configurations of the system 10 of FIG. 3 and examples of various
welding equipment included therewith. One of ordinary skill in the
art will appreciate that the system 10 and related methods
disclosed and/or claimed may be assembled in some configurations
using items of equipment that, individually, may be commercially
available. Embodiments of this disclosure are not, however, limited
to the specific items of equipment shown.
[0035] FIG. 4 is a side view of an example implementation of the
welding system of FIG. 3 as implemented for demonstration purposes
in a lab-type setting. The tubular workpiece 20 in this example is
a pipeline segment propped up on a stand 28. The arm 52 of the boom
50 is moveable in this example, to raise and lower the arm 52 and
the helper station 60 suspended therefrom. Electrical power and
data communication cables 54 are routed along the arm 52 from the
welding equipment on the skid 12 to the helper station 60. A
cabinet is provided for receiving the welding machines 30 and power
supply 40, with room for additional equipment. Alternatively, the
skid 12 could be shortened to further reduce the footprint of the
skid 12 where additional equipment capacity is not required. A user
may stand and work in a work area 18 with convenient access to the
tubular workpiece 20, the welding machines 30, the power supply 40,
and the helper station 60, while remaining within the work area
18.
[0036] FIG. 4 further illustrates an optional collapsible cover 90
that can be used at a remote worksite to help protect the user and
equipment. The collapsible cover 90 may be coupled to the boom 50
over the helper station 60. The collapsible cover 90 can be opened
to an expanded position 92 that covers an area overhead of one or
more of the helper station 60, the mechanized carrier 24 (FIG. 5),
and a portion of the tubular workpiece 20 including the weld path.
The collapsible cover 90 may be moved to a collapsed position as
indicated at 94 (dashed linetype shows it being moved between fully
open and fully closed), for transporting the system 10 to and from
the worksite 5.
[0037] FIG. 5 is a perspective view of the tubular workpiece 20 on
which the guide track 22 and mechanized carrier 24 are installed.
As can be seen, the guide track 22 in this example is generally
circular to conform to the generally circular outer diameter (OD)
of the tubular workpiece. The system 10 works with a tubular
workpiece 20 having a diameter as small as about 8 inches (20 cm).
For example, in cross-country pipeline welding 50 miles can be run
at 36 inch diameter.
[0038] An attachment mechanism is provided on the mechanized
carrier 24 for attaching the gasless torch 62 at the desired
position. An alternative configuration optionally allows for
interchangeably supporting the gasless torch 62 or one or more
other tools, such as a paint sprayer or a sand blaster. Thus, in
addition to being able to weld the tubular workpiece 20 using the
gasless torch 62, one of the other attachments may be used to paint
or sand-blast at least a portion of the OD of the tubular workpiece
20, such as along the weld path 26 of FIG. 3.
[0039] The gasless torch (FIG. 3) may be held on the right or left
side of the mechanized carrier 24. The gasless torch could be
located at any orientation to the mechanized carrier that allows
access to the tubular workpiece 20 and weld path 26. The guide
track 22 is offset a uniform distance "h" from the OD of the
tubular workpiece 20, to maintain the gasless torch a uniform
distance from the OD as the mechanized carrier 24 travels around
the tubular workpiece 12. In one or more embodiments, the guide
track 22 may have a certain amount of flexibility or
conformability, or may otherwise be pre-fabricated, to adapt to
workpiece cross-sections that may be slightly off-round or even
different shapes.
[0040] FIG. 6 is a side view of an example implementation of the
helper station 60 with various equipment installed on or connected
thereto. The helper station 60 is configured for use with a gasless
welding system and method as described herein, but, alternatively,
may support various welding equipment installed on or connected
thereto in association with a gas-shielded welding system or
method. The frame 61 of the helper station 60 is open in this
example, with space between the frame members to allow for ingress
and egress of various cabling and other features. A robust,
flexible guide cable 64 is provided for guiding the consumable
welding wire 72 as it is being fed from the automatic wire feeder
70. The guide cable 64 contains a housing lined with a polymer for
receiving the consumable welding wire along at least a portion of a
guide path from the wire feeder 70 to the gasless torch 62. A
sectional view of the flexible guide cable 64 shows an internal
example configuration including an outermost protective housing, an
inner housing 74 within the protective housing, and a polymer liner
such as a polytetrafluoroethylene liner 76 inside the inner housing
74. The consumable welding wire 71 is disposed within the
polytetrafluoroethylene liner 76, which facilitates uniform feeding
of the consumable welding wire 71 to the gasless torch. The uniform
feeding of the consumable welding wire 71 helps ensure a uniform
and stable wire feed rate (length of wire per unit of time) is
delivered to the workpiece. Since gasless welding is particularly
sensitive to wire feed speed and voltage at the workpiece, this
polytetrafluoroethylene-lined cable configuration is yet another
aspect that helps enable gasless welding approach that eliminates
the shack.
[0041] FIG. 7 is a side view of the automatic wire feeder 70
carried on the helper station 60. A panel is open to reveal the
consumable welding wire 71 coiled around a spool 73. The wire 71 is
fed from the spool 73 to the gasless torch via an injector 77.
[0042] FIG. 8 is an exposed view of a connection 66 of the gasless
torch 62 at which voltage is locally measured at the workpiece
instead of or in addition to at the welding machines. A voltage
sensor included on the gasless torch 62 senses an arc voltage at
the tubular workpiece. Due to impedance losses in electronic
cabling, the voltage measured at the gasless torch 62 is more
representative of the actual voltage of the arc than a voltage
taken at the welding machine. This helps ensure tighter and more
responsive control of the voltage to further facilitate a gasless
welding approach. The welding machine 30 of FIGS. 3 and 4 is
configured for adjusting the controlled voltage supplied by the
welding machine 30 to the torch 62 in response to the arc voltage
sensed by the voltage sensor. A difference between the controlled
voltage supplied by the welding machine 30 (FIG. 3) and the arc
voltage sensed by the voltage sensor in the gasless torch 62 in
some embodiments is less than +/-1 V.
[0043] FIG. 9 is a cutaway view of an example coaxial cable 80 for
facilitating low-impedance, high-accuracy control of the voltage at
the gasless torch connection. The coaxial cable comprises an inner
wire 82 disposed within an outer wire 84 and separated by an
insulating layer 85. The coaxial cable supplies the controlled
voltage from the welding machine 30 to the gasless torch 62 of FIG.
8.
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